Propellant composition containing triferrocenylmethyl perchlorate as catalytic oxidizer

ABSTRACT

Triferrocenylmethyl perchlorate as a partial or complete replacement for ammonium perchlorate and the standard burning rate catalyst in a propellant composition. Triferrocenylmethyl perchlorate functions as a combination burning rate catalyst and oxidizer.

States Patent 1 1 Jan. 14, 1975 PROPELLANT COMPOSITION CONTAININGTRIFERROCENYLMETHYL PERCHLORATE AS CATALYTIC OXIDIZER Inventor: David C.Sayles, Huntsville, Ala.

Assignee: The United States of America as represented by the Secretaryof the Army, Washington, DC.

Filed: Dec. 11, 1968 Appl. No.: 783,154

US. Cl.., 149/19.9, 149/2, 149/18, 149/l9.4, 149/19.5, 149/40, 149/42,149/44, 149/76 Int. Cl C06b 11/00 Field of Search 149/19, 20, 42, 75,98,

[56] References Cited UNITED STATES PATENTS 3,000,716 9/1961 Lawrence etal. 149/75 X 3,296,045 1/1967 Douda 149/75 3,305,413 2/1967 Flynn et a1149/19 Primary ExaminerStephen J. Lechert, Jr. Attorney, Agent, orFirm-Edward J. Kelly; Herbert Berl; Jack W. Voight [57] ABSTRACT 10Claims, N0 Drawings PROPELLANT COMPOSITION CONTAININGTRIFERROCENYLMETI-IYL PERCHLORATE AS CATALYTIC OXIDIZER BACKGROUND OFTHE INVENTION This invention relates to a novel burning rate catalystand particularly to a combination burning rate catalyst and oxidizer foruse in propellant compositions.

In the past, a large amount of work has been done in the area of highburning rate solid propellants. Most prior work has dealt with theeffects of propellant additives on the burning rates. These additiveshave included both chemical burning rate catalysts and short metallicfibers (staples). The use of chemical modifiers has often led to poorstability and/or reduced specific impulse. The use of metallic fibershas increased pro cessing difficulties and led to poor ballistic firingtraces. Accordingly, a high burning rate homogeneous propellant isgreatly desirable.

High burning rate homogeneous propellants which are easily castable havea number of applications in military weapons systems. Such high burningrate propellants are particularly suitable for use in high thrust tomass ratio motors.

Accordingly, it is the principal object of this invention to provide ahigh burning rate propellant which maintains good stability, processingand ballistic properties.

It is a particular object of this invention to provide such a highburning rate propellant which is homogeneous and has a high energybinder.

SUMMARY OF THE INVENTION It has been discovered that triferrocenylmethylper- Ammonium perchlorate 0-72 Aluminum 2-2O Binder 9-20Triferrocenylmethyl perchlorate 1-72 Three-dimensional crosslinking 0.5

agent Three-dimensional crosslinking agents (e.g., Tris(-methylaziridinyl) phosphine oxide and/orTris(oxiranyl)-para-aminophenol) provide crosslinking sitesin thepolymeric binder system to impart the desirable physical properties tothe solid propellant composition. The aforementioned compounds andothers known in the art facilitate the polymerization and hence areknown as polymerization catalysts. Also, a curing catalyst such as'ironlinoleate may be utilized. The iron linoleate is generally added inminor amounts to promote the curing of the binders and crosslinkingagents of the propellant composition. other catalyst (e.g., benzoylperoxide) for the three dimensional crosslinking agent may also be addedand a processing aid (e.g., lecithin) may be utilized as additives inminute amounts chlorate may be used as a partial or complete replace-(eachabout 0.1 percent, or less, by weight). Of course, ment forammonium perchlorate (or other oxidizer) the total weight percentages ofthe propellant ingrediand the standard burning rate catalyst in apropellant ents must be 100. composition. It functions as a combinationburning rate By the substitution of triferrocenylmethyl perchlocatalystand oxidizer, thereby enabling a larger proporrate for part (orall) ofthe oxidizer (preferably ammotion of the binder prepolymer to be usedwithout a sac- 40 nium'perchlorate) and the standard burning ratecatarifice in propellant burning rate. lyst (n-butylferrocene in theexample given), a larger proportion of the binder prepolymer is enabledto be DESCRIPTION OF THE PREFERRED used without a sacrifice inpropellant burning rate. This EMBODMENT represents a definite advantage.The resulting propel- Propellant compositions normally contain ammolantcomposition crystallizes at a lower temperature nium perchlorate (orother oxidizer), a metal staple adthan the prior art composition, themigration of the liqditive, a polymer binder, a burning rate catalyst,and a uid n-butylferrocene to the propellant burning surface processingaid. The binder is formed from a prepolyis reduced or eliminated, andpropellant degradation is mer reacted with a crosslinking agent in thepresence minimized. of a polymerization catalyst. It has been discoveredthat If desired, burning rate catalysts (or other additives) a largerproportion of the binder prepolymer is enabled such as copper chromitecan be incorporated into the to be used without a sacrifice inpropellant burning rate propellant composition in small amounts. byemploying triferrocenylmethyl perchlorate as a par- A specific example(compositionB) of this invention tial or complete replacement forammonium perchlois given in the following table. Composition A is aprorate (or other oxidizer) and the standard burning rate pellantcomposition which has been developed for a catalyst in the propellantcomposition. The triferhigh burning rate propellant, whereas compositionB is rocenylmethyl perchlorate functions as a combination a propellantcomposition which contains an equivalent burning rate catalyst andoxidizer. concentration of triferrocenylmethyl perchlorate. This Thepropellant compositions of this invention are example is merely intendedto be illustrative of this inpreferably composite (typically having acarboxyl-or vention and is not to be considered a limitation thereof.

Ingredient Composition A Composition B (wt. (wt.

Ammonium perchlorate, 6 68.0 62.0 Al 14.0 14.0

n-Butylferrocene 7.0 Triferrocenylmethyl perchlorate 6.3Carboxybterminated polybutadiene 10.5 17.2

prepolymer Continued lngredient Composition A Composition B (wt. (wt.

Tris(methylaziridinyl) phosphine 0.5 0.5 oxide ERLA- Iron LinoleateLecithin Tris(oxiranyl )-para-aminophenol Composition B is a propellantcomposition having the burning rate of composition A. However, it hasimproved mechanical properties and processing characteristics because alarger quantity of binder prepolymer is included in the propellantcomposition. Alternatively, if the binder content is not increased fullyfrom 10.5 to 17.2 percent, and a lesser amount of binder is used, anincrease in the ammonium perchlorate and/or aluminum content can beeffected, resulting in a propellant of higher burning rate and impulse.Correspondingly, if other burning rates are desired the standard amountof catalyst can be used, and the triferrocenylmethyl perchlorate can beused as a replacement for the ammonium perchlorate. Thus, the use oftriferrocenylmethyl perchlorate in a propellant composition provides ameans of simultaneously introducing both a burning rate catalyst and anoxidizer into that propellant composition. As noted above a decrease inammonium perchlorate can be accomplished without a loss of burning rate,and as a direct result of the decreased ammonium perchlorate thepropellant can contain a higher binder to fuel ratio which yields apropellant of improved physical properties. Also, the problem ofmigration of the n-butylferrocene can be minimized or eliminated sincethe amount of this liquid material used can be varied whentriferrocenylmethyl perchlorate is used in the propellant composition.

I claim: 7

LA solid propellant composition comprising a polymeric binder, a metal,and triferrocenylmethyl perchlorate.

2. The composition of claim 1 comprising an oxidizer in addition to saidtriferrocenylmethyl perchlorate.

3. The composition of claim 2 wherein said oxidizer is ammoniumperchlorate.

4. The composition of claim 3 wherein said metal is in the form ofstaples.

5. The composition of claim 3 wherein the weight percentage of saidammonium perchlorate is from about 60 to about 72 percent, and whereinthe weight percentage of said binder is from about 9 to about 20percent.

6. The composition of claim 5 wherein said metal is in staple form andwherein said metal staple is present in an amount of at least about 2weight percent.

7. The composition of'claim'6 wherein the weight percentage of saidmetal staple does not exceed about 20 percent.

8. The composition of claim 7 wherein the weight percentage of saidammonium perchlorate is about 62 percent, the weight percentage of saidmetal staple is about 14 percent, the weight percentage of saidtriferrocenylmethyl perchlorate is about 6 percent, and

wherein the weight percentage of said polymeric binder is about 17percent.

9. The composition of claim 8 wherein said polymeric binder is formedfrom a carboxyl-terminated polybutadiene prepolymer crosslinked with asuitable crosslinking agent.

10. The composition of claim 9 wherein said crosslinking agent istris-(methylaziridinyl)phosphine oxide.

2. The composition of claim 1 comprising an oxidizer in addition to said triferrocenylmethyl perchlorate.
 3. The composition of claim 2 wherein said oxidizer is ammonium perchlorate.
 4. The composition of claim 3 wherein said metal is in the form of staples.
 5. The composition of claim 3 wherein the weight percentage of said ammonium perchlorate is from about 60 to about 72 percent, and wherein the weight percentage of said binder is from about 9 to about 20 percent.
 6. The composition of claim 5 wherein said metal is in staple form and wherein said metal staple is present in an amount of at least about 2 weight percent.
 7. The composition of claim 6 wherein the weight percentage of said metal staple does not exceed about 20 percent.
 8. The composition of claim 7 wherein the weight percentage of said ammonium perchlorate is about 62 percent, the weight percentage of said metal staple is about 14 percent, the weight percentage of said triferrocenylmethyl perchlorate is about 6 percent, and wherein the weight percentage of said polymeric binder is about 17 percent.
 9. The composition of claim 8 wherein said polymeric binder is formed from a carboxyl-terminated polybutadiene prepolymer crosslinked with a suitable crosslinking agent.
 10. The composition of claim 9 wherein said crosslinking agent is tris-(methylaziridinyl)phosphine oxide. 